It is known that the Mediterranean diet (MD), which is characterized by high consumption of vegetables, fruits, cereals, beans, nuts, and olive oil, moderate consumption of fish, white meat, eggs, dairy products, and alcohol, and low consumption of red meat, processed meats, and foods rich in sugars or fats, can reduce the risk of cardiovascular diseases, type 2 diabetes, neurodegenerative diseases, and cancers. Previous epidemiologic studies had confirmed the protective role in the incidence and mortality of gastrointestinal cancers. This review discusses MD and gastrointestinal cancers risk through the studies which examined esophageal cancer, gastric cancer, pancreatic cancer, or colorectal cancer. According to recent studies, MD is associated with a significant reduction in the risk of gastrointestinal cancers. But there is a lack of decisive evidence for the association between MD and its adjuvant treatment effect for gastrointestinal cancers. Considering the complexity of tumor etiology, we propose to design more related researches and more comprehensive data, which include diet, exercise and psychological integrated researches to reveal the relationship between MD and cancer.